Washington (CNN) - President Barack Obama's address Wednesday from the steps of the Lincoln Memorial will commemorate the 50th anniversary of the Rev. Martin Luther King Jr.'s "I Have a Dream" speech, representing a symbolic moment in U.S. history.

On that day in 1963, when King and his fellow marchers attended what he labeled 'the greatest demonstration for freedom in the history of our nation," few in that crowd could have imagined that half a century later, the first African-American president of the United States would mark the occasion with a speech in the same location.

Washington (CNN) - Prosecutors hope to determine by Labor Day whether Virginia's first family broke any laws regarding a gift-giving scandal that has engulfed Gov. Bob McDonnell and tarnished the once-sterling reputation of the Republican politician, a source with knowledge of the matter told CNN.

Lawyers for McDonnell and his wife met with prosecutors in the city of Alexandria on Monday as the Justice Department sought clarity over previously undisclosed gifts given to the governor and his family by the chief executive of a troubled dietary supplement company.